Metal fixture for typewriter desks



April 1'8, 1933.

METAL FIXTURE FOR TYPEWRITER DESKS M. FOX

2 Sheets-Sheet 1 Wff/ I gwwnto/o M ar/z'n Er.

April 18, 1933. M. Fox

METAL FIXTURE FOR TYPEWRITER DESKS Filed Apri'l 8, 1951 2 Sheets-Sheet 2lsatentecl pr. 18, 1933 uNifTED STATES PATENrol-FICE MARTINYI'1`O.X,*OIE GHIGAGO,l ILLINOIS, ASSIGNOR TO THE SENG- COMIANY, OF

i CHICAGO, ILLINOIS 'l METAL FIXTURE non TYrEWnITEn DEsx's Applicationiiled April 8,71931. Serial No. 528,689.

My invention is an improvement in typewriterdesks of the well knownconstruction in'which the platform for the typewriter is supported byopposite pairs of link-connected bell crank levers carried by vplatesslidable on rails in a compartment so, as to provide for housing thetypewriter in its lowermost position and for elevating the same toposition for use in front of the desk, the'lifting of the platform andtypewriter being assisted by spiralsprings interposed between the rearbell crank lever and an arched bar connecting the plates fand forming apart of the carriage. Y Y

In the operation yof swinging typewriter supportsof this generalconstruction the bell crank levers .are locked by weighted pawlscooperating with the rails inthe horizontal movement Vof the carriage,the forward movementjof the latter to released position of the pawlsbeing stoppedV by engagement of the front rollers and forward ends ofthe plates with the corner posts of the compartment which are recessedIto receive said rollers and the forward ends of the plates and therepeated striking of these metal parts against the corner posts resultsin tearing out the wood as well as causing stress onfthe i roller.Furthermore., the operation ofa gravity pawl in' automatically engagingand releasing the bell crank levers is not reliable to the extentrequired for the effective manipulation of the platform.

It is the principal object of my invention therefore to improve theconstruction of the metal fixtures of a typewriter desk of thischaracter to increase the simplicity of construction for economy inproduction and reliability in operation; all asvhereinafter set forthand more specifically pointedV out in the appended claims.

In the accompanying drawings: Figurel 1 is a vertical longitudinalsectional view through the rear portion of a typewriter desk constructedin accordance with my invention, the plat-form for thev typewriter beingin housed position.

Fig. 2 Vis a sideview with the compartment broken .away to show themetal fiX- l tures controlling the operation of the platform, thecarriage being near the limit of forward movement from -housedfposi-1on. i Fig. 3 is a similar view with the carriage at the limit of itsforward movement.

Fig. 4 is a kdetail perspective view o-f one of the side plates of thecarriage.

5 is an edgeview thereof. Figs. 6 and 7' are like views of the locklngpawl. i The typewriter desk to receive the swingmg platform 1sconstructed to provide a comi partment 10 in which the typewriter ishoused, said compartment having front cornerposts 11, 1l and rear corner`posts 12v to which the sides 13, 13 and back wall 14 are attached, thefront of the compartment beling closed by a door (not shown) if sodesired. Attached to the front and rear corner postsare horizontal rails15, 15 supporting 70 the carriage comprising side plates 16, 16connected at theirrear ends by an arched crossbar 17, they saidv plateshaving grooved` rollers. 18, 19' at opposite ends thereof c0- operatingwith pins 20, 21 at opposite edges of the plates from the rollersrespectively for properly supporting the carriage in sliding engagementwith the-rails, and to these plates are pivoted'bell crank levers 22, 23the shorter members of which are connected by a link 24 while the longermembers are pivotally connected to a platform 25 on which the typewriteris supported, it being noted by reference to Figs. 1 and 2 that saidlonger members of the bell crank levers depend from the side plates ofthe carriage inthe lowered position of the platform for housing thetypewriter and swing forwardly and upwardly in elevating the platformand typewriter in position for using the latter, and that the liftingmovement of the platform is assisted by means of a pair of spiralsprings 26, 26 connected at one end to the arched bar 17 and at theother end to a crossbar 27 extending between the longer members of thebell crank levers at the rear end of the carriage.

For pivotally connecting the outer ends of the longer members of thebell crank levers to the platform metal strips 28 are screwed to theopposite edges of said platform and each plate is provided with anupstanding tongue 29 which is adapted to engage a fixture 30 attached tothe front corner posts for holding the platform in elevated position asshown in Fie". 3 of the drawings, said fixture being the conventionalform of catch.

For locking the bell crank levers in the lowered position of theplatform when it is being moved to and from housed position in the deskcompartment pawls 31 are pivoted at 31a; to the outer sides of theplates 16 and the projecting hook of each pawl is adapted to engage apin 32 on the bell crank lever 22, said pawl being automaticallyreleased by the tail-piece 33 entering a recess 84 in the underside ofthe rail at the limit of the forward movement of the carriage carryingthe platform. The pawl is shaped so as to be pivoted at the outer sideof the plate 16 with a lateral extension under the same adjoining thehook which engages the pin on the bell crank lever, and in the presentinstance the pawl is actuated by a short spiral spring 85 attached atits upper end to an apertured ear 36 projecting from the inner side ofthe plate with the lower end of said spring formed into a hook passedthrough an aperture 37 (Fig. 7 in the offset portion of the pawl. Thepawl is limited in its downward movement by a lug 38 projecting from theplate, and both the aforesaid apertured ear and stop-lug are stampedfrom the plate. Y

The forward ends of the rails 15 are let into recesses 39 in the frontposts 11 of the desk, said recesses being adapted to receive the forwardends of the side plates of the carriage, it being noted thatthe bellcrank levers are spaced from said plates by reason of the outwardlystamped bearings 40 which also permit of the connecting link 24 beinglocated between the plate and bell crank levers, and to prevent contactof the rollers 18 with the corner posts a laterally projecting stopmember 41 is bent from each plate. This arrangement therefore providessubstantial stop members at opposite sides of the platform which abutagainst the corner posts at one side of the recesses receiving the endsof the plates thus entirely relieving the rollers of any stress and alsopreventing the ends of the plates of the carriage from injuring thewood. Furthermore, inasmuch as the front rollers 18, 18 are disposedaway from the corner posts in the forward position of the carriage andthe aforesaid stop members engage the corner posts at one side of therecesses 39 obviating the necessity of providing recesses for therollers as required when the movement ofthe carriage is limited by saidrollers and ends of the plates, it is therefore apparent that but asingle recess is required to be cut into each corner post. Thisimprovement in addition to actuating the pawl by means of a spring andlimiting its locking movement simplifies the construction and providesfor a smooth and reliable operation of the mechanism which will increasethe durability of the several cooperating parts. n

The operation is similar to that of typewriter desks of this generalconstruction, that is to say in moving the platform and typewritercarried thereby from housed position within the compartment to elevatedposition for use in` front of the desk the platform is grasped and movedforward sliding the carriage on the rails until the stops 41 projectingfrom the side plates strike the corner posts at which time the forwardends of said side plates enter the recesses for the advanced position ofthe parts and the tailpiece of each pawl entering the recess in thelower edge of the rail and hook members of the pawls Iare therebyreleased from engagement with the bell crank levers permitting them toswing on their pivots for the lifting of the platform to elevatedposition where it is held by engagement of the tongue 29 with the catch30, and in this position the longer members of the bell crank levers aresubstantially perpendicular to their pivots for firmly supporting thetypewriter in position for use. The pawls are yieldingly but positivelyheld in released position by means `of the springs 35 so that in housingthe typewriterv the lowering of the platform will cause the pins 32 onthe bell crank levers 22 to engage the pawls which swing on their pivotsuntil the rear ends thereof strike the lugs 38 and the tail-piece is ona horizontal plane imme-V diately below the rails so that said pawlswill be engaged by the lower edges of the rails,Y

and thereby maintain the bell crank levers locked during the movement ofthe platform into and out of the compartment of the desk.

I claim Y In combination with a typewriter desk having a compartmentwith corner posts; at its forward end and recesses at the inner side ofsaid posts, of supporting rails at oppoioc posts at one side of therecesses for limiting the forward movement of the sliding plates,

and bell crank levers pivoted to the plates for,

swinging movement and to which the platform is pivoted; together with apawl pivoted to the plate and having a tail-piece entering a recess inthe rail, a spring for moving the pawl into engagement with the recess,and a lug struck from the plate and with which the paWl engages forlimiting the movement of the same in one direction,

saicl pavvl cooperating with a pin lon one of' the bell crank levers inthe lowered position of the platform.

MARTIN FOX.

